add a new window to TestImgui

modules/examples/GuiModules/TestImgui/src/TestImgui.cpp

@@ -81,5 +81,24 @@ void TestImgui::run() {
     else
         app->end();
 
+    {
+        ImGuiIO& io = ImGui::GetIO();
+        static float f = 0.0f;
+        static int counter = 0;
+
+        ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
+
+        ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
+
+        ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
+
+        if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
+            counter++;
+        ImGui::SameLine();
+        ImGui::Text("counter = %d", counter);
+
+        ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+        ImGui::End();
+    }
     ImGui::Render();
 }